/*
	.....
	(Multi-line comments)
	.....
	Compiling: g++ ...
	Execu....

	Goal: The program will calculate the area of a circle.

*/

#include <iostream>	//cin, cout, fixed, showpoint, endl
#include <iomanip>	// for setprecision

using namespace std; 

int main ()
{
	// 1. variable declaration
	const float PI = 3.14;
	cout << fixed << showpoint << setprecision(1);
	
	float radius, area;

	// 2. input
	cout << "Input the radius (-1 to quit): ";
	cin >> radius;

	while( radius > 0)	
	{
		// 3. computing
		area = PI * radius * radius;

		// 4. output
		cout << "The area is: " << area << endl;
		
		cout << "input the radius (-1 to quit): ";
		cin >> radius;
	}
	
	return 0;
}